Fundamental Study of Adsorption and Reaction for Selective Electrocatalytic Hydrogenations

The chemical products society relies on every day, including food products, cosmetics, fuels, and lubricants, require significant energy input and expensive production facilities. Today, the large majority of those processes are powered by heat, whereby a fuel is burned, and the resulting temperature increase causes the reaction to go faster. However, the United States is rapidly increasing the amount of electricity flowing on the grid, which makes it possible to consider driving these manufacturing processes using electricity instead of heat. This could have several transformative advantages, including lower energy costs, less expensive reactors, and the possibility to make new chemical products. To achieve these advantages, it is necessary to understand the differences in how a chemical reactant behaves in an electricity-driven process, compared to a heat-driven process. Tackett will study these differences using unique tools that enable him to track how chemicals look as they transform to desirable products. This information will enable him to design reactors that are specifically tuned to be driven by electricity, which would ultimately result in cheaper chemical manufacturing for consumers and require fewer resource inputs. Since these are emerging processes in the chemical industry, Tackett will incorporate what he learns into new lessons within standard chemical engineering courses. New research methods developed by this work will also be added to undergraduate research programs. Professor Brian M. Tackett of Purdue University is studying fundamental mechanisms for electrocatalytic hydrogenations of light hydrocarbons. The rapid increase in electricity available in the US makes it possible to reimagine many chemical manufacturing routes with efficient electrochemical processes, and hydrogenations are one of the most important reaction classes in the chemical industry. However, there is a lack of fundamental knowledge on the mechanistic nature of electrocatalytic hydrogenations for hydrocarbons and similar molecules, partly due to the lack of appropriate analytical tools. Tackett will investigate fundamental adsorption and reaction behavior for these reactions using a specifically configured electrochemical mass spectrometer. This system will enable him to understand reactivity differences between electrocatalysts that form bulk metal hydrides versus those that only adsorb hydrogen on the surface. The quantitative nature of the mass spectrometer will also enable rigorous mechanistic discrimination and kinetic parameter determination when coupled with microkinetic modelling for probe reactions like acetylene hydrogenation. Combining these fundamental insights will result in rational design strategies for multi-functional hydrogenation electrocatalysts that are suitable for selective hydrogenation of a broad range of substrate molecules. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.